Seal's fate on Halloween a reminder about strandings

On Halloween Eve, perhaps when thoughts of dead and gory things were in the minds of many people, a dead creature appeared on shore. It was an adult male gray seal.

The seal's coat coloration, its large horse-shaped head, and conical-shaped, un-serrated teeth indicated it was a gray seal. Its long arched snout suggested it was a male; female gray seals don't have such elongated snouts and have lighter colored coats with dark spots. Female gray seals are also about a third smaller than male gray seals.

It is not unusual for dead seals to wash up on Cape Ann's beaches, and the vast expanse of Coffin's Beach is a hotspot for seal strandings throughout the year. However, what was unusual about this seal was its vast size.

The seal measured nearly 7 feet long and likely weighed over 400 pounds, making this one of the largest seals to which the Whale Center of New England has ever responded. Overall, the seal appeared to be in good condition, and there was no evidence of external wounds except for some minimal damage from scavengers that had started to pick at the carcass before we arrived.

What impressed me the most about the seal — aside from its sheer size — were its flippers. The paddle-shaped front flippers were each over a foot long with long claws at the tips, where our fingernails would be. The hind flippers were even longer — over a foot and a half — and contained a large amount of webbing between each of the "toes."

When a seal spreads out its hind digits, the webbing between each digit expands to form a large triangular surface which the seal uses to propel itself through the water. This is one difference between seals and their fur seal and sea lion relatives. Seals have large hind flippers to propel themselves through the water, while fur seals and sea lions have large front flippers to move through the water.

Many of the seal's teeth - especially the canines and incisors - were worn down, indicating this may have been an old animal. Although we don't know the cause of this animal's death, we would like to think he lived a long life and sired many seal pups.

Gray seals have a polygynous mating system, meaning that each male will mate with many females during a single breeding season. One of the reasons for the large body size of males is that they compete with each other to obtain mating rights to females. In essence, bigger males will win more of these aggressive interactions and mate with more females.

Despite the loss of this adult seal, the overall gray seal population in the Western North Atlantic is abundant and totals approximately 250,000 individuals. In recent years, an increasing number of gray seals have been observed pupping (coming ashore to give birth) on islands off Nantucket, Martha's Vineyard, and Cape Cod.

If you see a live or dead stranded seal, dolphin, porpoise, or whale, please do not touch or approach the animal. Instead, please do what the residents of Coffin's Beach did and call the Whale Center of New England Stranding Hotline at 978-281-6351.

All marine mammals are protected under federal law and it is illegal to approach a stranded marine mammal within 50 yards. The Whale Center of New England is the official stranding response team for northeast Massachusetts.

Heidi Pearson, PhD, is assistant director and stranding coordinator with The Whale Center of New England, based on Harbor Loop in Gloucester. She can be reached via e-mail at heidi@whalecenter.org, via phone at 978-515-5001, or via fax at 978-281-5666.

Photos

Photo courtesy of Heidi Pearson This gray seal was found dead on CoffinÕs Beach in Gloucester on Halloween. Staff Photographer